Unmanned ground-based hygiene maintenance vehicle and method for improving hygiene conditions

ABSTRACT

An unmanned ground-based hygiene maintenance vehicle, UGV, includes a housing with a base plate, top plate and housing side wall substantially perpendicular to the base plate. Arranged in the housing is at least one wheel drive coupled to at least one wheel in a recess in the base plate. The UGV includes sensors for sensing the environment of the UGV, and a controller for autonomous location and navigation of the UGV based on sensing parameters of the sensors. The UGV includes an articulated robot arm on the top plate of the housing and to support a hygiene maintenance tool. The UGV includes at least one load-receiving element coupled to the housing side wall and extending outwards from the housing side wall, wherein the load-receiving element includes a load support surface for supporting a hygiene maintenance tool supply module with respect to a vertical direction extending transverse to the base plate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to both German Patent Application DE 10 2020 209 701.1 filed Jul. 31, 2020, and German Patent Application DE 10 2020 209 746.1 filed Aug. 3, 2020, the entire disclosures of which are incorporated by reference herein.

TECHNICAL FIELD

The disclosure herein relates to an unmanned ground-based hygiene maintenance vehicle, a cooperatively acting swarm of unmanned ground-based hygiene maintenance vehicles, and a method for improving hygiene conditions, for example in passenger compartments of transport vehicles such as aircrafts, in particular using a cooperatively acting swarm of unmanned ground-based hygiene maintenance vehicles.

Although applicable for any kind of action involved in hygiene practices or procedures, the disclosure herein and the corresponding underlying concepts and challenges will be explained in further detail mainly in conjunction with professional hygiene care processes on board of an aircraft.

BACKGROUND

In the end of 2019, the first cases of COVID-19 were identified in the district of Wuhan in the People's Republic of China. The virus spread rapidly, infecting tens of thousands of people in China. Spreading of the virus outside of China was first documented on Feb. 2, 2020 (Wu D, Wu T, Liu Q, Yang Z. The SARS-CoV-2 outbreak: what we know. International journal of infectious diseases: IJID: official publication of the International Society for Infectious Diseases. 2020). Currently, there are over 12 million confirmed cases of infections with COVID-19 worldwide.

Hygiene practices aiming to prevent or minimize spreading of an infectious disease such as COVID-19 are becoming more important, both for governmental bodies and regulators as well as for private corporations concerned about the medical care situation and the wellbeing of customers and employees alike.

When performing tasks under potentially hazardous circumstances, deployment of machines and/or autonomously acting robots is capable of mitigating risks for humans. Technical auxiliary systems such as exoskeletons or autonomous unmanned ground-based vehicles (AGVs) that may help under those circumstances are generally known from the prior art.

For example, JP H09-47413A discloses a cleaning robot including driving wheels or crawlers and a wiping unit for wiping the floor with a detergent or disinfectant. Document CN 111265707 A discloses an autonomously moving robot having a mobile chassis and several disinfection devices installed on the mobile chassis. Document US 2016/0271803 A1 discloses a mobile robotic platform having a UV emitting disinfection unit.

There is therefore a fundamental need for flexible and adaptive solutions for the unmanned, automatic performance of hygiene measures, in particular for upkeeping hygiene standards on board of passenger transport vehicles, which can be implemented reliably and efficiently in a confined space.

SUMMARY

One of the objects of the disclosure herein is therefore to find improved solutions for technical auxiliary systems in the improvement of hygiene conditions, in particular on board of passenger transport vehicles.

This and other objects are achieved by an unmanned ground-based hygiene maintenance vehicle (UGV), by a swarm of unmanned ground-based hygiene maintenance vehicles (UGVs), and by a method for improving hygiene conditions by one or more unmanned ground-based hygiene maintenance vehicles (UGVs) as described herein.

According to a first aspect of the disclosure herein, an unmanned ground-based hygiene maintenance vehicle (UGV) comprises a housing, having a base plate, a top plate and at least one housing side wall that is substantially perpendicular to the base plate. Arranged in the housing is at least one wheel drive, which is coupled to at least one wheel, in particular an omnidirectional wheel. The omnidirectional wheel may for example be realized as a Mecanum wheel. The at least one wheel is arranged in a recess in the base plate. The UGV comprises a plurality of sensors for sensing the environment of the UGV, and a controller for autonomous location, navigation and collision avoidance of the UGV on the basis of sensing parameters of the plurality of sensors. The UGV further comprises an articulated robot arm mounted on or through the top plate of the housing, the robot arm being configured to support at least one hygiene maintenance tool. The UGV further comprises at least one load-receiving element that is coupled to the housing side wall and extends outwards from the housing side wall. The at least one load-receiving element comprises a load support surface for supporting a hygiene maintenance tool supply module with respect to a vertical direction which extends transverse to the base plate.

According to a second aspect of the disclosure herein, a swarm of unmanned ground-based hygiene maintenance vehicles (UGVs) comprises a plurality of UGVs according to the first aspect of the disclosure herein, one of the plurality of UGVs performing the role of a lead vehicle, and the controller of the lead vehicle being connected to the controllers of the rest of the plurality of UGVs via wireless communication, and being designed to control the movements of the rest of the plurality of UGVs. Within the meaning of the disclosure herein, “control” also means coordinating the joint movement of the UGVs.

According to a third aspect of the disclosure herein, a method for improving hygiene conditions by one or more unmanned ground-based hygiene maintenance vehicles, for example in a passenger compartment of an aircraft, in particular by using a cooperatively acting swarm of unmanned ground-based hygiene maintenance vehicles (UGVs) such as, for example, according to the second aspect of the disclosure herein, comprises the steps of equipping at least one UGV according to the first aspect of the disclosure herein with at least one hygiene maintenance tool on the articulated robot arm and a hygiene maintenance tool supply module on the load-receiving element, connecting the equipped hygiene maintenance tools with the equipped hygiene maintenance tool supply module for each UGV, coordinating cooperative movement of the at least one UGVs, and using the equipped hygiene maintenance tools to perform local hygiene maintenance operations.

One of the concepts of the disclosure herein is to use autonomously acting hygiene maintenance vehicles having omnidirectional mobility in order to perform local hygiene maintenance operations at various points in an environment where hygiene conditions need be improved to or upheld at a certain hygiene level, such as, for instance, in a passenger compartment of an aircraft. For example, when all passengers have disembarked the aircraft after a flight leg, the performance of local hygiene maintenance operations in the passenger compartment of the aircraft may help raise the hygiene conditions back to a level deemed to be acceptable for safe re-embarking of other passengers for the next flight leg.

Due to their low unladen weight and compact design, the UGVs can be used in confined environments such as an aircraft. The UGVs have the advantage of excellent maneuverability and can therefore provide valuable support for human workers. Moreover, human workers may be partially or entirely replaced by the UGVs reducing the time and level of exposure of human workers to potentially unhygienic environments. Due to the modular implementation of robot arm interfaces and tool interfaces, the UGVs can be made suitable, in an adaptive and highly flexible manner, for a very wide range of hygiene maintenance operations. It is thus also possible to implement a single hygiene maintenance system, based on such UGVs, as a ground service system at an airport for multiple different types of aircraft. This allows a cost-efficient implementation of a technical assistance system for hygiene maintenance.

Advantageously, the UGVs may be built in such a way that the hygiene maintenance tool supply modules itself, i.e. for example accumulators, UV lighting units and/or disinfectant tanks, serve as a stabilizing frame. Since such hygiene maintenance tool supply modules are typically very heavy, this enables the UGVs to be of a light and compact construction while still maintaining a low center of gravity of the loaded UGVs overall.

In another advantageous embodiment, the loads of the hygiene maintenance tool supply, such as the amount of overall liquid disinfectant needed for hygiene maintenance or the capacity of an electrical energy storage, may be distributed over a number of smaller hygiene maintenance tool supply modules. Those loads can then be transferred to the transport surface, on which the UGV drives, not only via a single wheel of the UGV, but via a plurality of wheels, and thus a plurality of load application points. This can be advantageous, in particular, if the transport surface is sensitive to high loads. For example, a floor plate of a vehicle, in particular of an aircraft, should not be subjected to excessive loads. Thus, a load per area is advantageously reduced, in particular, when specific threshold values are prescribed or when particular sensitive transport surfaces are provided. For example, a load per area may be reduced to 25 kg per cm² or below. Of course, the disclosure herein is not limited to a threshold of 25 kg per cm².

The UGVs can form between them an ad-hoc network based on a wireless communication protocol, such that the number of UGVs can be increased or decreased dynamically and without specific modification, depending on the currently prevailing maintenance requirements. The UGVs themselves do not need to be reprogrammed or specially modified for this purpose, as a standardized and harmonized interface architecture is provided.

A great advantage of the UGVs is their high load-bearing capacity when lifting large loads in a small space. Owing to the integrated lifting mechanism, in combination with the fact that the load is received laterally, on the side of the housing, the center of gravity of the UGVs may be kept very low so that the reach of the articulated robot arm may be wider without the UGV being prone to tipping over.

Advantageous designs and embodiments are described with reference to the figures.

According to some embodiments of the UGV according to the disclosure herein the at least one load-receiving element may extend substantially parallel to the base plate. For example, the load-receiving element may also be substantially plate shaped. Optionally, the load support surface of the load receiving element may be planar. Further optionally, the load support surface may extend substantially parallel to the base plate, too. Other shapes or configurations of the load-receiving element are possible. For example, the load support surface may be curved, e.g. concave to receive pipes or similar, V-shaped, or similar.

According to some embodiments of the UGV according to the disclosure herein the at least one load-receiving element may be coupled to the housing side wall so as to be stationary relative to the base plate, at least with respect to the vertical direction. Optionally, the load-receiving element may be coupled to the housing side wall so as to be stationary relative to the base plate in all directions. That is, when lifting a hygiene maintenance tool supply module, the load-receiving element remains stationary relative to the housing of the UGV while the at least one wheel of the UGV is deflected relative to the base plate.

According to some embodiments of the UGV according to the disclosure herein the at least one load-receiving element may be detachably coupled to the housing side wall. Thus, various load-receiving elements, which may, for example, have support surfaces of different shapes, may be easily coupled to the housing side wall. Generally, the housing side wall may comprise a mechanical coupling interface configured to detachably couple at least one load-receiving element to the housing side wall.

According to some embodiments of the UGV according to the disclosure herein, the at least one housing side wall may have at least one T-profile or dovetail groove as a mechanical coupling interface, which extends parallel to the base plate and in which a T-profile or dovetail tongue rail of the at least one load-receiving element can be engaged in a form-fitting manner. Such a design allows different types of load-receiving elements to be exchanged quickly and without special tools, depending on the type and shape of hygiene maintenance tool supply modules to be transported. Owing to the T-profile or dovetail architecture of the load-receiving element interface, the load-bearing capacity of the load-receiving elements is particularly high.

According to some further embodiments of the UGV according to the disclosure herein, a tool carrier, having an electrical tool connection, may be arranged in the at least one housing side wall. In some embodiments, in this case an electrically operable suction pad may be connected to the electrical tool connection. Electrically operable suction pads can be applied to outer walls of the hygiene maintenance tool supply modules to prevent the hygiene maintenance tool supply modules from slipping off the load-receiving elements.

Further embodiments of the UGV according to the disclosure herein may be equipped with exactly four wheels, which are coupled to four wheel drives and arranged in a recess in the base plate. By providing more than one wheel, the pressure applied to the transport surface on which the wheels roll can be advantageously decreased. By providing exactly four wheels a highly stable stand of the UGV and improved traction can be achieved.

According to some other embodiments of the UGV according to the disclosure herein, the wheel drive of the UGVs may comprise at least one wheel suspension and at least one lifting motor. Each wheel may be suspended on one wheel suspension and at least one lifting motor may be provided for or coupled to each wheel. In particular, each lifting motor may be kinematically coupled to one wheel so as to deflect the wheel relative to the housing in the vertical direction. According to some embodiments, at least two lifting motors serve to deflect the wheel suspension relative to the housing in a direction perpendicular to the floor plate. Generally, the lifting motors allow the wheel to be extended in a controlled manner through the recess in the base plate in order to raise the housing, with the received module, from the floor.

According to some further embodiments of the UGV according to the disclosure herein, the wheel suspension may comprise two wheel suspension arms, which are connected to the housing via two sawtooth-threaded rods coupled to the two lifting motors. The lifting motors can be, for example, stepper motors, which can adjust a precise lifting height of the load via the sawtooth-threaded rods. Alternatively, the lifting motors may be realized as servo motors, for example, or, generally as an electric motor. Sawtooth threads are trapezoidal threads having two differing flank angles, of 30° to 45° on the one hand, and 0° to 3° on the other hand. Such sawtooth threads can absorb high forces when loaded on the flatter thread flank and, in particular in this case, are particularly advantageous for lifting mechanisms for raising heavier modules, such as electrical energy storages or liquid disinfectant tanks, in the vertical direction. The disadvantage of easier detachability is of scarcely any significance in the case of vertical lifting movements.

According to some embodiments of the UGV according to the disclosure herein, the UGV may comprise at least two wheels and an inclination sensor configured to capture an inclination of the base plate relative to a predefined reference direction, wherein the controller may be configured to control the lifting motors coupled to the wheels such that the inclination of the base plate relative to the reference direction is kept within a predefined range. The reference direction may for example be the direction of gravity or a direction perpendicular to an even region of the transport surface on which the UGV drives. By controlling the lifting motors based on the captured inclination, the base plate and, thereby, the load-receiving element can be kept in a desired, predefined orientation. For example, the predefined inclination range may include an angle range of 5 degrees relative to the reference direction. Generally, controlling the inclination of the UGV eases movement over uneven regions of the transport surface and prevents the UGV from unwantedly tipping over.

According to some further embodiments of the UGV according to the disclosure herein, the controller may have a wireless communication module, via which the controller of one UGV can exchange data with a controller of another UGV. Via the wireless communication modules, a plurality of UGVs can perform maintenance operations together in a cooperative manner, in that important movement parameters of the individual UGVs can be exchanged, optionally in real time, among the group of UGVs involved in the transport. For example, if at least two UGVs are used, one lead vehicle (“master”) and a plurality of follower vehicles (“slaves”) can be defined. Possibly, a cooperative mode of operation may also be realized by synchronizing the system times of the individual UGVs to the master UGV and, based on this, “timing” the movements according to predefined movement plans within the area within which the hygiene maintenance operations should be performed. The lead vehicle in this case assumes control of the movements of the follower vehicles by wireless communication with the controller of the follower vehicles.

According to some embodiments of the unmanned transport system according to the disclosure herein a base station including an electrical charging interface may be provided, wherein the UGVs may comprise an electrical energy storage device, for example for operating the lifting motors, the controller, the sensors and so on, and an UGV charging interface configured to be coupled to the electrical charging interface of the base station for charging the electrical energy storage device. Optionally, the electrical charging interface of the base station and the UGV charging interface may be configured for inductive charging. For example, the base station may comprise a charging interface including a charging plate and a charging inductor coil arranged beneath the charging plate or integrated into the charging plate. The UGV may comprise a receiving inductor coil arranged on or integrated into the base plate of the housing the UGV charging interface. For charging the electrical energy storage device may simply drive onto the charging plate of the base station. Thus, charging can be performed autonomously in a very simple manner.

The above designs and embodiments may be combined with each other in any appropriate manner. Further possible designs, embodiments and implementations of the disclosure herein also include combinations of features of the disclosure herein not explicitly mentioned above or described below with regard to the example embodiments. In particular, persons skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the disclosure herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure herein is described in greater detail in the following on the basis of the example embodiments given in the schematic figures.

FIG. 1 shows a schematic perspective view of the exterior of an unmanned ground-based hygiene maintenance vehicle according to some embodiments of the disclosure herein;

FIG. 2 shows a schematic perspective view of the exterior of an unmanned ground-based hygiene maintenance vehicle according to some embodiments of the disclosure herein;

FIG. 3 shows a schematic illustration of the components present in the interior of an unmanned ground-based hygiene maintenance vehicle according to some embodiments of the disclosure herein;

FIGS. 4A and 4B show schematic illustration of two operating states of the unmanned ground-based hygiene maintenance vehicle of FIG. 3 during the raising of modules to be transported;

FIG. 5 shows a schematic perspective view of the exterior of an unmanned ground-based hygiene maintenance vehicle according to some embodiments of the disclosure herein;

FIG. 6 shows a schematic perspective view to a base plate side of an unmanned ground-based hygiene maintenance vehicle according to an embodiment of the disclosure herein;

FIGS. 7A through 7D show schematic illustrations of four operating states of the unmanned ground-based hygiene maintenance vehicle of FIG. 6 during the raising and transporting of hygiene maintenance tool supply modules to be transported;

FIG. 8 shows of the components present in the interior of an unmanned ground-based hygiene maintenance vehicle shown in FIGS. 6 and 7;

FIG. 9 shows a schematic perspective view of the exterior of an unmanned ground-based hygiene maintenance vehicle according to a further embodiment of the disclosure herein;

FIG. 10 shows a schematic perspective view of the exterior of an unmanned ground-based hygiene maintenance vehicle according to a further embodiment of the disclosure herein;

FIG. 11 shows a schematic perspective view of the exterior of an unmanned ground-based hygiene maintenance vehicle according to a further embodiment of the disclosure herein;

FIG. 12 shows a schematic perspective view of the exterior of an unmanned ground-based hygiene maintenance vehicle according to a further embodiment of the disclosure herein;

FIG. 13 shows a a schematic perspective view of the exterior of an unmanned ground-based hygiene maintenance vehicle according to some embodiments of the disclosure herein;

FIG. 14 shows an explosion view of components of unmanned ground-based hygiene maintenance vehicles according to some embodiments of the disclosure herein;

FIG. 15 schematically illustrates a functional block diagram of a transportation system according to an embodiment of the disclosure herein; and

FIG. 16 schematically illustrates a functional block diagram of unmanned ground-based hygiene maintenance vehicle according to an embodiment of the disclosure herein.

The appended figures are intended to provide a further understanding of the embodiments of the disclosure herein. They illustrate embodiments and, in combination with the description, serve to explain principles and concepts of the disclosure herein. Other embodiments and many of the stated advantages are evident from the drawings. The elements of the drawings are not necessarily shown in true scale in relation to each other. Terminology indicating direction, such as “top”, “bottom”, “left”, “right”, “above”, “below”, “horizontal”, “vertical”, “front”, “rear” and similar indications are used merely for explanatory purposes and are not intended to limit the universality to specific configurations as shown in the figures.

In the figures of the drawing—unless otherwise specified—elements, features and components that are identical, functionally identical and that act in an identical manner are in each cased denoted by the same reference numerals.

DETAILED DESCRIPTION

Unmanned hygiene maintenance vehicles, within the meaning of the disclosure herein, in this case include driverless vehicles which, for the purpose of transporting hygiene maintenance tool supply modules loaded on the vehicles to execute local hygiene maintenance operations, perform ground-based movement operations such as, for instance, changes of direction, acceleration or braking maneuvers, substantially without human involvement or intervention, for example with the aid of sensors and software, integrated in the transport vehicle, for location, navigation, obstacle detection and path planning.

FIG. 1 shows a schematic perspective view of the exterior of an unmanned ground-based hygiene maintenance vehicle (UGV) 100. FIG. 3 shows a schematic illustration of the components present in the interior of the UGV 100. FIGS. 6 to 8 show a further UGV 1000, wherein FIGS. 6 and 7A through 7D show schematic perspective views of the exterior of the UGV 1000 and FIG. 8 shows a schematic illustration of the components present in the interior of the UGV 1000. FIG. 16 shows a functional block diagram of an UGV 100, 1000.

As shown for example in FIG. 16, an UGV 100, 1000 may comprise a housing 1, 1001, at least one wheel drive 10, at least one wheel 13, a controller 15, and a plurality of sensors S. Optionally, an electrical energy storage device 16 and an UGV charging interface 120 may be provided, too. The UGV 100, 1000 comprises at least one load-receiving or load-bearing element 6 which is configured to support an item to be transported and which is coupled to the housing 1, 1001 of the UGV 100, 1000. In particular, the load-receiving element 6 may be detachably coupled to the housing, for example, such that it is stationary relative to the housing 1, 1001 in the coupled state. The wheel drive 10 is kinematically coupled to the at least one wheel 13, 130 and configured to drive the wheel 13, 130 in order to move the UGV 100, 1000 on a transport surface. Further, the wheel drive 10 may be configured to deflect the at least one wheel 13, 130 so that the housing 1, 1001 can be lifted together with the load-bearing element 6 in order to lift an item supported by the load-receiving element 6.

As can be taken from FIG. 16, the wheel drive 10 may include at least one wheel suspension 14 and at least one lifting motor 11. Generally, each wheel 13, 130 may be coupled to an individual wheel suspension and one or more lifting motors 11 may be provided per wheel 13, 130. Operation of the wheel drive 10 may be controlled by controller 15, for example, based on sensor data captured by sensors S. The controller 15, the lifting motors 11, and, as far as necessary, the sensors S may be supplied with electrical energy from the electrical energy storage device 16, which may, for example, be a battery, an accumulator, or similar. The electrical energy storage device 16 may be charged via the UGV charging interface 120.

The controller 15 may comprise, for example, an ASIC, an FPGA or any other suitable computing means or processor. The controller 15 serves to control and monitor the wheel drive, sensors and other electronic or electrical components of the UGV 100.

The sensors S may, for example, include a pyroelectric sensor 3 that provides information about nearby heat sources and that can thus be used to protect human workers in the vicinity of the UGV. Other sensors, in particular environmental sensors for capturing information about the surrounding of the UGV, such as, for instance, radar sensors, ultrasonic sensors, optical sensors, IR sensors, laser sensors, lidar sensors or other types of sensors may be provided at different positions and in different arrangements on the UGV 100, 1000. Without limitation of the universality, sensors 2 a and 2 b are shown in FIG. 16. Further optionally, an inclination sensor 8 may be provided. The sensors for environment sensing advantageously may also be used for navigation purposes. For example, the controller 15 may receive the sensor data from the environment sensors and control operation of the wheel drive based on the captured sensor data. For example, during movement of the UGV in an area within which hygiene maintenance operations are to be performed by the UGV, the sensors may capture information representing a state of contamination or cleanliness of the surfaces and objects in the vicinity of the UGV with respect to a level of hygiene.

An UGV 100, 1000 may be used alone or in combination with at least one further UGV 100, 1000 for performing hygiene maintenance tasks. Since each UGV 100, 1000 comprises sensors S, each UGV 100, 1000 may navigate autonomously. When used in combination with other UGVs 100, 1000, each UGV 100, 1000 may be equipped with an individual load-receiving element 6 in order to easily couple with an interface of a hygiene maintenance tool supply module to be transported. Of course, all UGVs 100, 1000 may also be equipped with the same type of load-receiving element 6. Optionally, sensor information captured by the UGVs 100, 1000 may be shared between UGVs 100, 1000 which cooperatively share workload in hygiene maintenance tasks, for example, via a wireless communication module 15A of the controller 15.

Due to its outstanding maneuverability, for example, because of employing omnidirectional wheels 13, 130, the UGV 100, 1000 can easily navigate within a passenger compartment of an aircraft in between seat rows. Similar, the UGV 100, 1000 may be used in performing hygiene maintenance tasks within other transport vehicles, such as ships, trains, or busses. Of course, other use cases of the UGV 100, 1000 are possible, too. For example, the UGV 100, 1000 may perform hygiene maintenance tasks in indoor environments, such as in warehouses, supermarkets, offices, laboratories, hospitals, and so on, or in outdoor environments, such as airports, train stations, harbors, mines, and so on.

As shown for example in FIGS. 1 through 4, essentially, the UGV 100 comprises a housing 1, having a base plate 1 c, a top plate opposite to the base plate 1 c and at least one housing side wall 1 a that is substantially perpendicular to the base plate 1 c. The housing 1 may have, for example, a substantially box-shaped structure, possibly having rounded corners, on the other side faces, i.e. on the side walls that complete the housing 1 to form a closed enclosure for the internal components. In particular, the top plate may not be entirely flat but may have a curved or partially stepped or corrugated surface. Arranged in the recess 1 d in the floor plate 1 c there is a wheel 13, which is suspended inside the UGV 100, for example by a wheel suspension 14 having two suspension arms 14A, 14B.

The wheel 13 may be, for example, an omnidirectional wheel such as, for instance, a so-called Mecanum or lion wheel, which has a number of barrel-shaped rollers mounted rotatably on the circumference of the wheel 13 at an angle of inclination in relation to the main axis of rotation of the wheel 13. The rollers provide contact with the ground or transport surface. The rollers can rotate freely about the inclined bearing axis. The wheel 13 as such is driven via a wheel drive 10 inside housing 1 with variable direction of rotation and variable rotational speed.

Alternatively, however, for this purpose it may be possible to realize the wheel 13 as an individually steered wheel having a controllable rotary suspension for rotating the wheel running axle perpendicular to the ground. For example, the wheel 13 may be integrated as a drive wheel into a travel/turn module which, in addition to the rotary movement of the drive wheel, also permits an additionally active vertical axis rotation capability and alignment. The wheel drive in this case may have two separate drive motors, one of which drives the drive wheel of the travel/turn module, while the other effects its alignment about the vertical axis. The capability to rotate about the wheel running axle and the vertical axis is endless in each case, and thus enables continuous movement of the wheels without end positions. Alternatively, to implement omnidirectional mobility of the UGV 100, the wheel 13 may also be realized as an all-side wheel, i.e. as a wheel attached to the main circumferential surface of which are a number of auxiliary wheels, the axes of rotation of which are at right angles to the main axis of rotation of wheel 13.

The UGV 100 may comprise a plurality of sensors for environment sensing. For example, attached to the top of the housing 1 there may be pyroelectric sensor 3 that provides information about nearby heat sources and that can thus be used to protect human workers in the vicinity of the UGV. Other sensors such as, for instance, radar sensors, ultrasonic sensors, optical sensors, IR sensors, laser sensors, lidar sensors or other types of sensors may be integrated into the housing 1 of the UGV 100 at different positions and in different arrangements. Without limitation of the universality, sensors 2 a and 2 b are represented, as examples, on different side walls of the UGV 100 in FIGS. 1 to 4. It may be possible to include air pollution sensors in the UGV 100. Such air pollution or air quality sensors are devices that monitor the presence of air pollution in the surrounding area, particularly in order to detect and quantify particulate matter in the air. For example, the air quality sensors may be capable of sampling the air in the surrounding of the UGV 100 in order to determine a level of contamination by germs, viruses, bacteria spores and similar pathogens or microorganisms in the air.

The UGV 100 may comprise a controller 15 for autonomous location and navigation of the UGV 100 on the basis of sensing parameters of the plurality of sensors. The controller 15 may comprise, for example, an ASIC, an FPGA or any other suitable computing means or processor. The controller 15 serves to control and monitor the wheel drive, sensors and other electronic or electrical components of the UGV 100.

In one of the housing side walls 1 a—shown facing forwards in FIGS. 1 and 2—there may be one or more grooves 5, running parallel to the base plate 1 c. These grooves 5 serve to receive one or more load-receiving elements 6. FIG. 1 shows two load-receiving elements 6 a, 6 b, each representing outwardly projecting load-receiving forks 6 a and 6 b. In FIG. 2, only one load-receiving element 6 is shown, as a widened load-receiving platform or plate 6 c. The load receiving elements 6 a, 6 b, 6 c each comprise a substantially even support surface 60 in order to support an item with respect to a vertical direction extending perpendicular to the base plate 1 c. FIG. 12 exemplarily shows a load-receiving element 6 in the form of a substantially wedge-shaped component 6 d protruding outwardly from the housing side wall 1 a. The wedge-shaped component 6 d may comprise a concave curved support surface 60 which extends outwardly from and inclined relative to the housing side wall 1 a. Thus, the support surface 60 of the wedge-shaped component 6 d is configured to support an item with respect to the vertical direction. Optionally, a counterpart 61 may be coupled to the housing side wall 1 a, 1001 a in addition to the wedge-shaped component 6 d. As shown for example in FIG. 12, the counterpart 61 may extend in the vertical direction along the housing side wall 1 a, 1001 a and include a concave curved end section arranged opposite to the support surface 60. Generally, the at least one load-receiving element 6 of the UGV 1, 1001 may comprise a load support surface 60 for supporting an item with respect to a vertical direction which extends transverse to the base plate 1 c, 1001 c.

As is further shown in FIGS. 1, 2 and 12, the load-receiving elements 6 a, 6 b, 6 c may have anti-slip features provided at the load receiving surface 60, e.g. an anti-slip material 62 (FIG. 12) and/or fluted profiles (FIGS. 1 and 2). It may also be possible to tilt or incline the load-receiving elements 6 relative to the horizontal.

The grooves 5 may be, for example, T-profile or dovetail grooves, in which T-profile or dovetail tongue rails of the respective load-receiving elements 6 a, 6 b, 6 c can engage in a form-fitting manner. For this purpose, the tongue rails can be pushed into the grooves 5 from the outside. The grooves 5 may run parallel to the base plate 1 c and at different distances from the base plate 1 c, parallel to each other, to enable different load bearing heights to be flexibly adapted to the cargo to be transported. Generally, the at least one load-receiving element 6 is detachably coupled to the housing side wall 1 a. In particular, the at least one load receiving element 6 may be coupled to the housing side wall 1 a so as to be stationary relative to the base plate 1 c, at least with respect to the vertical direction.

A tool carrier 4 a may also be arranged in the housing side wall 1 a. The tool carrier 4 a, optionally, may have an electrical tool connection, i.e. for the purpose of supplying electrical power, the connection may be connected, via electrical lines, to an electrical energy storage device 16 such as, for instance, a battery or accumulator, inside housing 1. The electrical energy storage device 16 may also provide an independent power supply for the other electrical and electronic components of the UGV 100. The tool carrier 4 a may be movable in the vertical direction relative to the base plate 1 c, e.g. by a carrier lift motor (not shown) kinematically coupled to the tool carrier 4 a.

A great variety of tools may be attached to the tool connection. FIG. 2, by way of example, illustrates an electrically operated suction pad 4 b, which is connected to the electrical tool connection. The suction pad 4 b may be, for example, a vacuum suction pad that rests against a flat outer surface of the item to be transported and that enables improved handling of a hygiene maintenance tool supply module by a vacuum between the suction surface and the outer surface. FIG. 9 shows for example a horizontal stop 4 c coupled to the tool carrier 4 a, which may be pivotal about an axis extending in the vertical direction. The stop 4 c may be used to support an item to be transported with respect to direction parallel to the base plate 1 c, 1001 c. FIG. 10, by way of example, shows a vertical stop or clamp element 4 d coupled to the tool carrier 4 a. The clamp element 4 d may serve for clamping an item between the clamp element 4 d and the support surface 60 of the load-receiving element 6. FIG. 11 exemplarily shows a magnet interface 4 e coupled to the housing side wall 1 a, 1001 a. The magnet interface 4 e may include a carrier plate 40 mechanically coupled to the side wall 1 a, 1000 a and a magnet device 41, in particular an electromagnet, coupled to the tool carrier 4 a. The carrier plate 40 may be detachably coupled to the side wall 1 a, 1001, for example, by the T-profile or dovetail groove 5 in the same fashion as described above for the load-receiving element 6. The magnet device 41 may be mechanically and/or electrically coupled to the tool carrier 4 a. Thus, the magnet device 41 can be activated, e.g. supplied with electrical energy by the tool carrier 4 a, and, optionally, be moved relative to the carrier plate 40, in particular in the vertical direction, by the tool carrier 4 a. Further, FIG. 12, by way of example, shows the counterpart 62 to be coupled to the tool carrier 4 a. Further examples for tools may include manipulators, for example, manipulator arms which enable manipulation of the items, for example, gripping and rotating of the items.

As shown for example in FIGS. 3 and 4, two lifting motors 11 may be provided inside housing 1, to enable the item to be raised after the item has been loaded onto the load-receiving elements 6. These lifting motors 11 are configured to deflect the wheel suspension arms 14A, 14B, relative to the housing 1, in a direction perpendicular to the base plate 1 c, that is, in the vertical direction. For example, the wheel suspension arms 14A, 14B may be connected to the housing 1 via two sawtooth-threaded rods 12 coupled to the two lifting motors 11, such that the lifting motors 11 can shift the wheel suspension arms 14 up or down along the course of the sawtooth-threaded rods 12, and thus retract or extend the omnidirectional wheel 13 from the recess 1 c. The lifting motors 11 may be electric motors such as, for example, stepper motors or servo motors. The UGV 100 shown for example in FIGS. 1 through 4A,4B comprises exactly one wheel 13. One wheel drive 10 is provided for this wheel 13, including one wheel suspension 14 and two lifting motors 11. Generally, also for the case that more than one wheel is provided, the wheel drive 10 may comprise at least one wheel suspension 14 per wheel and at least one lifting motor 11 per wheel, wherein each lifting motor 11 is kinematically coupled to one wheel so as to deflect the wheel relative to the housing 1 in the vertical direction.

Two possible operating states of the lifting motors 11 are represented in scenarios FIGS. 4A and 4B—firstly, in scenario 4A, where the wheel suspension 14 is located at the upper end of the sawtooth-threaded rods 12, such that the omnidirectional wheel 13 is completely, or almost completely, accommodated inside the housing 1, i.e. the distance of the base plate 1 c from the floor is zero, or at least very small. Following actuation of the lifting motors 11, the wheel suspension 14 is moved downwards along the sawtooth-threaded rods 12 by rotational movement, such that the omnidirectional wheel 13 moves out of the recess 1 d, downwards out of housing 1, and thus the entire housing 1 is raised from the floor until the full lifting height is attained, in scenario 4B.

The controller 15 of the UGV 100 may include a wireless communication module 15A (FIG. 16), via which the controller 15 of a first UGV 100 can exchange data with a controller 15 of a second UGV 100. In particular, different UGVs 100 may each be designated as a lead vehicle (“master”) or follower vehicle (“slaves”), such that the controller 15 of the lead vehicle is connected to the controller 15 of the follower vehicles via wireless communication, and can control and monitor the movements of the follower vehicles. For example, sensor data captured by the sensors S may be shared between the UGVs 100 via the wireless communication module 15A.

In the cooperative movement of the UGVs, one of the UGVs 100 may assume the role of lead vehicle. The controller 15 of the lead vehicle communicates, via wireless communication, with the controller 15 of the other UGVs 100, and can issue movement commands to the follower vehicles.

FIGS. 5 and 13 schematically illustrate an UGV 100, 1000 having an articulated robot arm mounted on the top plate of the housing 1. The UGVs 100, 1000 in FIGS. 5 and 13 may have all or at least some of the properties and characteristics of the UGVs 100 or 1000 as depicted in any of the FIG. 1 through 4A,4B or 6 through 12. Example perspective views of the embodiments of FIGS. 5 and 13 are shown FIG. 14.

The UGVs 100, 1000 in FIGS. 5 and 13 include an articulated robot arm 22, 52 that is mounted on or through top of the top plate of the housing. The articulated robot arm 22, 52 may be—as shown—a robot containing rotary joints that may commonly be referred to as axes. An articulated robot arm 22, 52 may be for example a two-axis structure or may be more complex with a number of three or more axed. The articulated robot arm 22, 52 may be powered by servo motors. For example, the articulated robot arm 22, 52 may have six axes that each provides an additional degree of freedom, i.e. a possibility for independent motion of the robot arm. The axes may for example be arranged in a chain allowing a previous chain node to support a subsequent node along the robot arm structure. The structure of the articulated robot arm 22, 52 may begin in a base aligned vertically to the top plate of the housing and containing a first revolute joint. The main robot arm body may be connected to the base through this first revolute joint. A second revolute joint may run perpendicular to the main robot arm body connecting a shoulder portion to the main robot arm body.

The shoulder portion includes a third parallel revolute joint at its end which may be used to attach the shoulder portion to the main robot arm body. Additional joints or axes may then be used at the end of the robot arm to attach a robot wrist and an end effector 23, 53. The end effector 23, 53 may be used to attach a hygiene maintenance tool such as a disinfectant spray tool 23 or a UV lighting unit 53.

The robot arm 22, 52 may be directly mounted with its base portion to the top plate of the housing 1. Alternatively, it may be possible to mount the base portion of the robot arm 22, 52 to an inner structure of the UGV 100, 1000 and provide for a spare-out in the top plate of the housing through which the remainder of the robot arm 22, 52, in particular the main robot arm body may be guided to the outside of the housing 1.

A hygiene maintenance tool supply module 21, 51 may be carried on the load-receiving element 6 at the side of the housing. The hygiene maintenance tool supply module may for example be a liquid disinfectant tank 21 that may be connected to the disinfectant spray tool 23 at the end effector of the robot arm 22 by a liquid disinfectant supply line 24, such as a plastic tube or similar. The hygiene maintenance tool supply module may in another example be an electric energy supply module 51 including a battery or accumulator and corresponding supply circuitry for providing power to a UV lighting unit 53 at the end effector of the robot arm 52. The electric energy supply module 51 may be connected to the UV lighting unit 53 at the end effector of the robot arm 52 by an electric supply line 54, such as a power cable or similar.

In case of UGVs 100, 1000 having only a single wheel 13 or just two wheels 13 arranged in line, it may be possible for two or more UGVs 100, 1000 concomitantly docking to a single hygiene maintenance tool supply module. For example, two UGVs 100, 1000 each having two wheels 13 arranged in line may connect to opposite sides of a single hygiene maintenance tool supply module so that the load-receiving element 6 at the side of the housings 1 of the two UGVs 100, 1000 may together carry the single hygiene maintenance tool supply module by supporting it from the opposite sides. That way, the hygiene maintenance tool supply module may be carried in the middle between the two UGVs 100, 1000 balancing out the center of gravity of the resulting vehicle. In a similar manner, a number of four UGVs 100, 1000 each having a single wheel only may connect to a single hygiene maintenance tool supply module from different sides resulting in a compound vehicle of four UGVs 100, 1000 carrying a single hygiene maintenance tool supply module balanced in the middle.

As illustrated in FIG. 13, the UGV 100, 1000 may additionally be equipped with a number of further UV lighting units 55 that are distributed around and at the surface of the housing. Those further UV lighting units 55 may—together with the UV lighting unit 53 at the end effector of the robot arm 52—be used to irradiate everything in the vicinity of the UGV 100, 1000 as effectively and as extensively as possible with UV light that can kill or deactivate organic particulate matter like germs, viruses, bacteria or similar microorganisms.

Due to maneuverability and the compact volume, the UGV 100, 1000 of FIGS. 5 and 13 may be very suitable for gaining access to all of the cabin area in a passenger compartment of an aircraft, for purposes of performing hygiene maintenance operations. The process autonomy of the UGV 100, 1000 renders it possible to automate any hygiene maintenance processes so that human workers may advantageously be removed from the processes that might pose potential danger to the workers due to UV-C radiation or aerosolized disinfectants. The UGV 100, 1000 of FIGS. 5 and 13 may change its equipped tools and supply modules fairly quickly and easily due to the plug-and-play functionality of the robot arm and the load-receiving element.

FIGS. 6 through 8 show an embodiment 1000 of a UGV that has an arrangement of four wheels 130. The mobility of the UGV 1000 in all directions results from the fact that a UGV 1000 has four specially arranged Mecanum wheels. It may also be possible to provide the UGV with individually steered wheels having a controllable rotary suspension for rotating the wheel running axle perpendicular to the ground. Generally, the UGV 100 may comprise four omnidirectional wheels. The essential elements and the mode of operation of the UGV 1000 are essentially the same as those of the UGV 100 described in connection with FIGS. 1 through 5, with a housing 1001, having a base plate 1001 c, a top plate and at least one housing side wall 1001 a substantially perpendicular to the base plate 1001 c, being likewise provided. On the rest of the side surfaces, i.e. on the side walls that complete the housing 1000 to form a closed enclosure for the internal components, the housing 1000 may have, for example, a substantially box-shaped structure, possibly having rounded corners. Arranged in the recess or recesses 1001 d of the base plate 1001 c are four wheels 130, which are suspended by wheel suspensions 14 inside the UGV. Such a design is advantageous, for example, if the load of a hygiene maintenance tool supply module to be carried is transferred to the floor—for example a floor of a passenger compartment within an aircraft—not only via one wheel of the UGV, but via a plurality of wheels, and thus a plurality of load application points.

In FIGS. 7A through 7D, it is shown that the wheels 130 can be lowered or retracted by lifting motors. It is possible in this case to arrange them on two axles, but the wheels may also be controlled, or raised and lowered, individually, for example by aid of the wheel suspension 14 provided for each wheel. FIGS. 7A through 7D show various operating states. Thus, scenario FIG. 7A shows retracted wheels 130, FIG. 7B scenario shows the wheels 130 extended, and FIGS. 7C and 7D scenarios show either the front or the rear wheels 130 retracted when, at the same time, the wheels 130 on the other axle are extended. Such axle wise or wheel wise raising or lifting of the wheels 130 may be advantageous when passing uneven portions of a floor surface, e.g. when passing a sill or gap. In particular, the lifting motors 11 coupled to the wheels may be controlled so as to keep the base plate 1001 c basically horizontal. As is schematically shown in FIG. 16, the UGV 1000 may comprise an inclination sensor 8 configured to capture an inclination of the base plate 1001 c relative to a predefined reference direction, i.e. the direction of gravity. For example, the inclination sensor 8 may include three electronic acceleration sensors which measure an acceleration along three perpendicular axes. The controller 15 of the UGV 1000 receives the measured or captured inclination of the base plate 1001 c and controls the lifting motors 11 coupled to the wheels 130 such that of the base plate 1001 a relative to the reference direction is kept within a predefined range. Optionally, when a swarm of cooperatively controlled UGVs 1000 is used to perform hygiene maintenance operations, the UGVs 1000 may communicate the inclination of their base plates to each other and further a lifting value of each of their wheels 130, wherein the controller 15 of the lead UGV is configured to issue control commands to each UGV 1000 of the swarm of UGVs 1000 for controlling the lifting motors 11 of each UGV 1000.

FIG. 8 shows a detailed view of the interior of the UGV 1000. Inside the housing 1001, the drive mechanism or wheel drive 10 and the lifting and lowering mechanism or wheel suspensions (not visible in FIG. 8) are arranged in a compact design. Also provided are energy storage devices, which enable the UGV 1000 to move independently.

As already discussed above various hygiene maintenance tools and corresponding hygiene maintenance tool supply modules can be transported by a method using a cooperatively acting swarm of UGVs. This method can be carried out by all types of UGVs 100, 1000 described above, irrespective of the number of wheels 13, 130. When UGVs 1000 having more than one wheel 130 are used, at least two UGVs 1000—e.g. UGVs 100 as represented and explained in FIG. 5 or 13—are equipped with at least one hygiene maintenance tool on the articulated robot arm 22, 52 and a hygiene maintenance tool supply module 21, 51, on the load-receiving element 6. The equipped hygiene maintenance tools 22, 52 are then connected to the equipped hygiene maintenance tool supply modules 21, 51 for each UGV 100; 1000, respectively.

Cooperative movement of the at least two UGVs 100, 1000 is then coordinated in order to be able to use the equipped hygiene maintenance tools 23, 53 of the at least two UGVs 100, 1000 to perform local hygiene maintenance operations. The hygiene maintenance tool supply module is placed in a suitable manner on the load-receiving elements 6 of the UGVs 1000, such that the module can be raised in a coordinated movement by the lifting motors 11 of the UGVs 1000. In particular, the wheels 13 are deflected relative to the base plate 1001 c in the vertical direction. The item, raised thus, can then be moved by cooperative control of the omnidirectional wheels 130 of the at least two UGVs 1000, for example within a passenger compartment of an aircraft to perform local hygiene maintenance or improvement operations such as cleaning, decontaminating and/or disinfecting objects in the passenger cabin or surfaces within the passenger cabin.

A method as described above, for example, may be carried out by an unmanned hygiene maintenance system, UHMS, 200 including two or more UGVs 100, 1000. FIG. 15 schematically shows an UHMS 200 comprising four UGVs 100, 1000 and a base station 210. Of course, other more or less than four UGVs 100, 1000 may be provided. The UGVs 100, 1000 may be configured as described above. The base station 210 may comprise an electrical current supply 230, at least one electrical charging interface 220 for charging the UGVs 100, 1000, and an optional tool changer 240.

The charging interfaces 230 may comprise a charging plate 221, onto which the UGV 100, 1000 can drive and park, and a charging inductor coil 222 arranged beneath the charging plate 221 or integrated into the charging plate 221. The charging interfaces 220 are electrically connected to the current supply 230 of the base station 210. Optionally, a controller (not shown) may be provided for controlling operation of the charging interfaces 230.

The UGV 100, 1000 may comprise an UGV charging interface 120 which is only schematically shown in FIG. 16. Generally, the UGV charging interface 120 is configured for being connected to the charging interfaces 230 of the base station 220. Optionally, the UGV charging interface 120 is configured for being autonomously connected to the charging interfaces 230 of the base station 220. For example, the UGV charging interface 120 may comprise a receiving inductor coil (not shown) arranged on or integrated into the base plate 1 c, 1001 d of the housing the UGV charging interface 120. For charging the electrical energy storage device 14, the UGV may simply drive onto the charging plate of the base station. Thus, charging can be performed autonomously in a very simple manner.

The optional tool changer 220 may include a magazine holding various tools, for example, suction pads 4 b (FIG. 2), stop elements 4 c (FIG. 9), clamp elements 4 d (FIG. 10), magnet interfaces 4 e (FIG. 11), counterparts 62 (FIG. 12), and so on. An UGV 100, 1000 of the UHMS 200 may autonomously drive to the tool changer 220 and couple the respective tool to its tool carrier.

In the preceding detailed description, various features have been combined in one or more examples to improve the stringency of the presentation. It should be clear in this case, however, that the above description is merely illustrative, and is in no way restrictive. It serves to cover all alternatives, modifications and equivalents of the various features and exemplary embodiments. To persons skilled in the art, because of their technical knowledge, many other examples will be immediately and directly obvious upon consideration of the above description.

The example embodiments have been selected and described in order to best illustrate the principles underlying the disclosure herein and its possible applications in practice. This enables experts to modify and use the disclosure herein and its various examples of execution in an optimal manner with respect to the intended purpose. In the claims, as well as in the description, the terms “including” and “having” are used as neutral language terms for the corresponding terms “comprising”. Furthermore, use of the term “one” is not in principle intended to exclude a plurality of such described features and components.

While at least one example embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the example embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a”, “an” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority. 

1. An unmanned ground-based hygiene maintenance vehicle, UGV, comprising: a housing having a base plate, a top plate and at least one housing side wall that is substantially perpendicular to the base plate; at least one wheel drive, which is in the housing; at least one wheel, which is coupled to the at least one wheel drive and in a recess in the base plate; a plurality of sensors for sensing an environment of the UGV; a controller for autonomous location and navigation of the UGV on a basis of sensing parameters of the plurality of sensors; an articulated robot arm mounted on or through the top plate of the housing and configured to support a hygiene maintenance tool; and at least one load-receiving element that is coupled to the housing side wall and extends outwards from the housing side wall, the at least one load-receiving element comprising a load support surface for supporting a hygiene maintenance tool supply module with respect to a vertical direction which extends transverse to the base plate.
 2. The UGV according to claim 1, wherein the at least one load-receiving element extends substantially parallel to the base plate.
 3. The UGV according to claim 1, wherein the at least one load-receiving element is coupled to the housing side wall to be stationary relative to the base plate, at least with respect to the vertical direction.
 4. The UGV according to claim 1, wherein the at least one load-receiving element is detachably coupled to the housing side wall.
 5. The UGV according to claim 4, wherein the at least one housing side wall comprises at least one T-profile or dovetail groove, which extends parallel to the base plate and which is configured to receive a T-profile or dovetail tongue rail of the at least one load-receiving element in a form-fitting manner.
 6. The UGV according to claim 1, wherein a tool carrier, having an electrical tool connection, is in the at least one housing side wall.
 7. The UGV according to claim 6, further comprising an electrically operable suction pad that is connected to the electrical tool connection.
 8. The UGV according to claim 1, wherein the wheel drive comprises at least one wheel suspension and at least one lifting motor, wherein each wheel is suspended on one wheel suspension, and wherein the at least one lifting motor is provided for each wheel, each lifting motor being kinematically coupled to one wheel to deflect the wheel relative to the housing in the vertical direction.
 9. The UGV according to claim 8, wherein the at least one wheel suspension comprises two wheel suspension arms, which are connected to the housing via two sawtooth-threaded rods coupled to two lifting motors provided for the wheel.
 10. The UGV according to claim 8, wherein the UGV comprises at least two wheels and an inclination sensor configured to capture an inclination of the base plate relative to a predefined reference direction, wherein the controller is configured to control the lifting motors coupled to the wheels such that the inclination of the base plate relative to the reference direction is kept within a predefined range.
 11. The UGV according to claim 1, wherein the UGV comprises exactly four wheels, which are coupled to four wheel drives, each wheel being arranged in one recess in the base plate.
 12. The UGV according to claim 1, wherein the hygiene maintenance tool supply module is an electrical energy storage, a UV radiation emitting unit or a liquid disinfectant tank.
 13. The UGV according to claim 1, wherein the hygiene maintenance tool is a UV radiation emitting unit, an air quality sensor or a liquid disinfectant spray gun.
 14. The UGV according to claim 1, the controller having a wireless communication module, via which the controller of one UGV is configured to exchange data with a controller of another UGV.
 15. An unmanned hygiene maintenance system, comprising a plurality of UGVs according to claim 14, one of the plurality of UGVs performing a role of a lead vehicle, and a controller of the lead vehicle being connected to the controllers of the rest of the plurality of UGVs via wireless communication, and being configured to control movements of a rest of the plurality of UGVs.
 16. The unmanned hygiene maintenance system according to claim 15, further comprising a base station including an electrical charging interface, wherein the UGVs comprise an electrical energy storage device and an UGV charging interface configured to be coupled to the electrical charging interface of the base station for charging the electrical energy storage device.
 17. A method for improving hygiene conditions by using a cooperatively acting swarm of unmanned ground-based hygiene maintenance vehicles, UGVs, the method comprising: equipping at least one UGV according to claim 1 with at least one hygiene maintenance tool on the articulated robot arm and a hygiene maintenance tool supply module on the load-receiving element; connecting the equipped hygiene maintenance tools with the equipped hygiene maintenance tool supply module for each UGV; coordinating cooperative movement of the at least one UGVs; and using the equipped hygiene maintenance tools of the at least one UGVs to perform local hygiene maintenance operations.
 18. The method according to claim 17, wherein the method uses at least two UGVs and wherein one of the at least two UGVs performs a role of a lead vehicle, a controller of the lead vehicle being connected to the controllers of a rest of the plurality of UGVs via wireless communication, and being configured to control movements of the at least one other UGVs.
 19. The method according to claim 17, wherein the local hygiene maintenance operations involve irradiating surfaces in a local environment of the UGV with UV radiation and/or spraying liquid disinfectant on surfaces in the local environment of the UGV.
 20. The method according to claim 17, further comprising equipping an air quality sensor on the articulated robot arm and measuring air quality in the local environment of the UGV using the equipped air quality sensor. 